Design Ideas

Unique joists to steel the show

The NASCC Steel Conference will be held next month at Nashville's new Music City Center. The center features a grand entryway fabricated using arched barrel joists designed and manufactured by New Millennium. The special profile steel joists add a dramatic aesthetic note to the facility – and a cost savings to the project that was just as dramatic.

The NASCC Steel Conference will be held next month at Nashville's new Music City Center. The center features a grand entryway fabricated using arched barrel joists designed and manufactured by New Millennium. The special profile steel joists add a dramatic aesthetic note to the facility – and a cost savings to the project that was just as dramatic.

Building a better steel experience

Nashville's new Music City Center shows off the design possibilities of steel construction, while putting a spotlight on the advantages of proactive steel joist design and delivery.

The grand entryway utilizes barrel joists supplied by New Millennium and fabricated by Indianapolis-based Lenex Steel. According to Jason Turk, Lenex Steel's senior project manager who handled the documentation for the fabrication of the facility's entryway, New Millennium's approach helped the project achieve tens of thousands of dollars in cost savings.

Turk explained that the vertical structural steel transitions into a pitched and sloped roof, so it was critical for New Millennium to get the joist angles correct. Contract drawings were only about 50 percent complete when Lenex Steel began steel fabrication. So New Millennium needed to proactively manage the steel joist detailing and Request for Information (RFI) process with the engineer of record to compress the timeline to delivery. Then New Millennium managed the delivery of the special joists, scheduling and providing day-of deliveries in sync with project erection.

Application Notes

Field modifications are loaded questions

This field photo shows the end web primary tension member of a steel joist that is not properly fitted over the bearing member. The erection crew made this modification prior to contacting the structural engineer or the steel joist company. A carefully guided field modification was then conducted to address this serious structural concern.

Important questions need to be addressed when making field modifications to load-bearing steel joist and deck structures. Here's what you need to know to assure the most successful and cost-saving field modifications.

1. Know why modifications occur and why they are important

Joist modifications in the field can arise due to errors in detailing, fabrication, or erection. They can also occur when relocating a roof top unit or due to building design changes after fabrication. Field conditions requiring open web steel joist modifications are usually very time sensitive. Erection schedules are being delayed and emotions are high, giving rise to the temptation to modify joists without structural engineer of record approval or joist manufacturer input.

2. Involve the right people immediately and fully

If the proper information is provided when the situation arises, the joist manufacturer can coordinate with the structural engineer of record as needed to provide a quick solution and keep the project moving. The highly-trained and experienced engineers employed by Steel Joist Institute (SJI) member companies are more than willing to discuss options and provide advice. The joist manufacturer can help with the analysis and any needed modification details. Most joist manufacturers have specialized programs for steel joist stress analysis. The joist supplier can also provide cost estimates for the analysis and any needed modification details prior to beginning work.

Take advantage of a proven, cost-saving approach

The Steel Joist Institute provides several resources to anyone seeking information on this topic. From the Joist Investigation Form that is used to help identify older joists in the field, to Technical Digest #12 "Evaluation and Modification of Open Web Joists and Joist Girders" and even webinars on this topic, SJI can be a good starting place for assistance in locating the proper joist manufacturer and for gathering general modification related information. For more information on SJI resources, please visit their web site at steeljoist.org

Did You Know?

Clearing away the RFI clouds is job won

Structural steel joist and deck design questions are communicated by circling points within the structural drawing (clouds), to pursue clarification by the engineer of record (EOR). A structural steel building project can be clouded by a prolonged Request for Information (RFI) process.

A structural steel building project can be clouded by delays when 1) the joist company is not involved early in the design process, and 2) when the Request for Information (RFI) process is not well managed. In view of the fact that structural drawings are often incomplete, a better-managed process is critical to overall building performance, overall building cost, and the earliest possible date for building occupancy and revenue generation.

A survey completed by New Millennium in December found that what steel fabricators value most, even above competitive joist and deck pricing, is the fact that New Millennium can bulldog the steel joist and deck RFI process to get it done quickly and with optimal design kept in mind.

The frequent need for steel joist and deck RFI process management was supported by a separate survey of construction professionals conducted by New Millennium early last year. The study found that of the 192 surveyed, 32% said that the structural steel drawings from the engineer of record (EOR) were seldom complete – making RFI resolution a frequent key step to on-time project delivery.

Incomplete drawings and prolonged RFI cycles have long been characteristic of traditional bid-build project delivery. Unlike more-evolved methods, the traditional bid-build process has pushed important steel joist, deck and beam design engineering considerations downstream away from the building team's early design phase. However, when New Millennium is involved early on the project as a structural steel design team member, the need for RFI collaboration is further minimized and the progression of this process is optimized, along with improved building performance, cost, timeline and the earliest possible building occupancy.